Australia’s top intelligence official has given an extraordinary warning about an “unprecedented” level of foreign espionage targeting Australians.

ASIO boss Mike Burgess revealed in his latest annual threat assessment that his agency had disrupted a “hive of spies” in the past year.

He said ASIO was “busier than ever before”, including the Cold War.

“Busier than any time in our 74-year history. Busier than the Cold War; busier than 9/11; busier than the height of the caliphate,” Mr Burgess said in a speech on Tuesday night.

“Based on what ASIO is seeing, more Australians are being targeted for espionage and foreign interference than at any time in Australia’s history.

“More hostile foreign intelligence services, more spies, more targeting, more harm, more ASIO investigations, more ASIO disruptions. From where I sit, it feels like hand-to-hand combat.”

Among the targets have been journalists, military veterans and judicial figures, he said.

No ‘top guns’

Mr Burgess also hit out at veterans who were selling their military training and expertise to foreign governments.

The issue had come to public attention recently with media reports Western pilots had been approached by China to train its military.

“These individual are lackeys — more ‘top tools’ than ‘top guns’,” Mr Burgess said.

“Selling our war-fighting skills is not different to selling our secrets — especially when the training and tactics are being transferred to countries that will use them … against us or our allies at some time in the future.”

He said in some cases former insiders had been stopped from travelling overseas to provide the training.

“But (in other cases) legal ambiguities have impeded law enforcement’s ability to intervene.”

He noted the overwhelming majority of veterans were Australian patriots in every sense.

“A small but concerning number are willing to put cash before country,” the spy chief said.

“Third-party companies have offered Australians hundreds of thousands of dollars and other significant perks to help authoritarian regimes improve their combat skills.”

He said since the announcement of AUKUS — the security cooperation deal between Australia, the US and UK — there had been a “distinct uptick in the online targeting of people working in Australia’s defence industry”.

“As we progress AUKUS, it’s critical our allies know we can keep our secrets, and keep their secrets.”

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Defence Minister Richard Marles said last week he had asked his department to review its policies to stop former soldiers and personnel sharing classified information with foreign powers.

He has also flagged possible law changes.

Mr Burgess said his concerns were not limited to the defence sector.

“If we are to take security seriously, Australia needs to ensure its laws and obligations prevent former insiders transferring any form of sensitive know-how to authoritarian regimes,” he said.

ASIO chief Mike Burgess delivers his annual assessment of Australia’s spy threats. Photo: AAP

Rising ‘domestic terrorism’

Mr Burgess said it was “almost guaranteed” that the nation’s domestic terrorism threat level would be raised in the future.

Late last year, Mr Burgess lowered the terrorism threat level from probable to possible – a decision that wasn’t taken lightly.

Although Australia remained a potential terrorist target, he said, there were fewer extremists with the intention to conduct an attack onshore than there were when the threat level was raised in 2014.

At the time of making the threat change, Mr Burgess said it remained “entirely plausible” there would be a terrorist attack in Australia within 12 months and that ASIO’s biggest concern was individuals and small groups who could move to violence without warning.

“Tragically, all that came true just a few weeks later.”

The Wieambilla tragedy – resulting in the murders of two Queensland police officers and a member of the public – in December showed how even with a lower threat level tackling terrorism remained challenging.

Mr Burgess described the shootings, carried out by Gareth, Nathaniel and Stacey Train, as an “act of politically motivated violence, primarily motivated by a Christian violent extremist ideology”.

But ASIO did not find evidence the killers embraced a “racist and nationalist ideology or were Sovereign Citizens, despite their anti-authority and conspiratorial beliefs”.

More broadly, he said the reach of extremist content online meant individuals were radicalising within days or weeks.

“So the time between flash to bang is shorter than ever,” Mr Burgess said in his latest annual threat assessment, delivered in Canberra on Tuesday.

“The radicalisation of minors is another concerning trend.”

The ASIO boss warned terrorism developments overseas could resonate in Australia.

“In our near region, under ISIL’s influence, religiously motivated violent extremists are adapting their methods, with suicide bombings becoming more common in the southern Philippines, as well as attacks by females and families in the region more broadly,” Mr Burgess said,

“Despite strong counter-terrorism pressure in the Philippines and Indonesia, ISIL-aligned violent extremists will continue to plan and conduct simple, often opportunistic attacks, primarily directed against local security forces and sectarian targets over the next six months.”

Terrorism hotspots in Africa, the Middle East and South Asia – where many Australians live and work – were also being watched.